Forums
 

Solve this equation > 48÷2(9+3) = ?


View Poll Results: Which is right?
2 663 55.76%
288 526 44.24%
Voters: 1189. You can't vote on this poll right now - are you signed in?

Reply
 
Thread Tools Search this Thread
Old 09-04-2011, 14:47   #151
Baldrick Phd
Forum Member
 
Join Date: Jun 2007
Location: TYNESIDE
Services: Helping Fluffers find the Higgs Boson
Posts: 18,091
Quote:
Originally Posted by TheRave View Post
The order of mathematics:
http://www.purplemath.com/modules/orderops2.htm

The last example applies directly to this discussion.

Again it explains that 16 ÷ 2(2) is ambiguous.

And then goes on to say:

"The general consensus among math people is that "multiplication by juxtaposition" (that is, multiplying by just putting things next to each other, rather than using the "×" sign) indicates that the juxtaposed values must be multiplied together before processing other operations. But not all software is programmed this way, and sometimes teachers view things differently. If in doubt, ask!"
Quote:
Originally Posted by 5th Horseman View Post
Only because of the ambiguity of how the original sum was written, the only way to clarify the answer is to write the sum in either of the long forms.
I would never have found this ambiguous until this discussion.

I consider the 2(2) to be bracketed therefore would be worked out first rather than 16/2 x 2.

Worrying that professional maths guys are talking about ambiguity as maths is supposed to be an exact science.


Hawking and Penrose at Cambridge, oops forget all that Blackhole and space/time business, we had a bracket in the wrong place
Baldrick Phd is offline   Reply With Quote
Please sign in or register to remove this advertisement.
Old 09-04-2011, 14:49   #152
munta
Forum Member
 
Join Date: Oct 2003
Location: Here there and everywhere
Services: Michaelwood M5
Posts: 13,195
Quote:
Originally Posted by TheRave View Post
So the answer is 288 or 2.

It completely depends on the interpretation of the priority of juxtaposed values.

The original sum requires clarification before answering completely.

FINISH

DONE

Hopefully we can all agree
Yes, with the caveat that I'm sticking to the answer given by Excel, SQL, IBM Cognos, SPSS & TM1. Since If I disagreed with them then my job would be impossible. And that answer is 288
munta is online now   Reply With Quote
Old 09-04-2011, 14:51   #153
John259
Forum Member
 
Join Date: Nov 2003
Location: Norwich, Norfolk, UK
Services: LG LCD IDTV; Tacolneston TX; Virgin Media ADSL
Posts: 11,037
It's 288.

Biffo and Rave - sorry but you are totally wrong, probably because you were taught incorrectly.

2(9+3) is exactly the same as 2 x (9+3), i.e. 2 x 12 = 24 (where x is a multiplication sign). However, with literal numbers it should be written with a multiplication sign. It's only with a letter before the opening bracket that the multiplication sign should be omitted.

BTW it's not an equation and you can't solve it. It's an expression and you evaluate it. It isn't calculus, nor is it A level material. Forty years ago it would have been around the second year of secondary school but that may have changed now.
John259 is offline   Reply With Quote
Old 09-04-2011, 14:56   #154
Bedlem
Inactive Member
 
Join Date: Jun 2010
Location: Down with man-flu.
Posts: 2,338
Quote:
Originally Posted by TheRave View Post
So the answer is 288 or 2.

It completely depends on the interpretation of the priority of juxtaposed values.

The original sum requires clarification before answering completely.

FINISH

DONE

Hopefully we can all agree
Nope, I'm sticking with what I originally said!

I agree that it's ambiguous but just apply a little logic...

What is '2(9 + 3)' on its own? Remove the rest of the equation and what does '2(9 +3)' mean? The fact that it isn't seperated by '2 + (9 + 3)' or '2 * (9 + 3)' or any other arrangement, indicates that '2(9 + 3)' is a single 'a(x + y)' string and, as such, I'd work it out as follows

2(9 + 3)
=>2*9 + 2*3
=>18 + 6
=>24

2(9 + 3) = 24.

Ergo

48 / "2(9 + 3)" = 2 because it isn't seperated like:
48 / 2 + (9 + 3)
48 / 2 * (9 + 3)

or any other such arrangement which would lead to other answers.
Bedlem is offline   Reply With Quote
Old 09-04-2011, 14:57   #155
VioletSummers
Forum Member
 
Join Date: Jan 2011
Posts: 862
Quote:
Originally Posted by John259 View Post
It's 288.

Biffo and Rave - sorry but you are totally wrong, probably because you were taught incorrectly.

2(9+3) is exactly the same as 2 x (9+3), i.e. 2 x 12 = 24 (where x is a multiplication sign). However, with literal numbers it should be written with a multiplication sign. It's only with a letter before the opening bracket that the multiplication sign should be omitted.

BTW it's not an equation and you can't solve it. It's an expression and you evaluate it. It isn't calculus, nor is it A level material. Forty years ago it would have been around the second year of secondary school but that may have changed now.
I still stand by what I say that it's 2. Simple BODMAS - you do the brackets first and that leaves 2.
BIB - Yep, it's around year 8/9 maths, depending on higher or lower sets, so it's not changed.
VioletSummers is offline   Reply With Quote
Old 09-04-2011, 14:58   #156
VioletSummers
Forum Member
 
Join Date: Jan 2011
Posts: 862
Quote:
Originally Posted by Bedlem View Post
Nope, I'm sticking with what I originally said!

I agree that it's ambiguous but just apply a little logic...

What is '2(9 + 3)' on its own? Remove the rest of the equation and what does '2(9 +3)' mean? The fact that it isn't seperated by '2 + (9 + 3)' or '2 * (9 + 3)' or any other arrangement, indicates that '2(9 + 3)' is a single 'a(x + y)' string and, as such, I'd work it out as follows

2(9 + 3)
=>2*9 + 2*3
=>18 + 6
=>24

2(9 + 3) = 24.

Ergo

48 / "2(9 + 3)" = 2 because it isn't seperated like:
48 / 2 + (9 + 3)
48 / 2 * (9 + 3)

or any other such arrangement which would lead to other answers.
THIS! I think Iove you..

God, I'm such a maths nerd
VioletSummers is offline   Reply With Quote
Old 09-04-2011, 14:59   #157
husted
Forum Member
 
Join Date: Aug 2008
Posts: 5,157
The point of brackets is to clarify the expression to make clear what should be done first. But if you have a number outside, then this needs to be operated on everything inside the brackets :
So if you have:
2(9+3)
then this is the same as
2x9 + 2x3.
But this isnt clear, so we write this as :
(2x9) + (2x3)

So a clearer way to put the expression might be

48 ÷ ((2x9) + (2x3))

which equals 2.
husted is offline   Reply With Quote
Old 09-04-2011, 15:03   #158
patsylimerick
Forum Member
 
Join Date: Sep 2010
Posts: 11,898
7 pages on THIS? It's 2 by the way.
patsylimerick is offline   Reply With Quote
Old 09-04-2011, 15:05   #159
The 12th Doctor
Forum Member
 
Join Date: Jan 2010
Location: Northumberland
Posts: 2,305
It's 2.
The 12th Doctor is offline   Reply With Quote
Old 09-04-2011, 15:05   #160
Bedlem
Inactive Member
 
Join Date: Jun 2010
Location: Down with man-flu.
Posts: 2,338
Quote:
Originally Posted by VioletSummers View Post
THIS! I think Iove you..

God, I'm such a maths nerd
Hey, it's just my opinion! I dropped out of Maths when I was 15 so understand that I'm 'uneducated' but applying my own logic.

(But yeah, the answer is still 2)
Bedlem is offline   Reply With Quote
Old 09-04-2011, 15:05   #161
John259
Forum Member
 
Join Date: Nov 2003
Location: Norwich, Norfolk, UK
Services: LG LCD IDTV; Tacolneston TX; Virgin Media ADSL
Posts: 11,037
Quote:
Originally Posted by husted View Post
So a clearer way to put the expression might be

48 ÷ ((2x9) + (2x3))
That is wrong, because the 2 is outside the brackets in the original expression, not inside them.
John259 is offline   Reply With Quote
Old 09-04-2011, 15:07   #162
Biffo the Bear
Forum Member
 
Join Date: Jul 2005
Location: Nottinghamceistershire
Services: Fusion powered warp drive
Posts: 21,627
Quote:
Originally Posted by John259 View Post
That is wrong, because the 2 is outside the brackets in the original expression, not inside them.
Ah, but it's okay to add a multiplication sign which wasn't there before?

Like I said earlier, if you're going to say:

Well, 2(3+9) is the same as 2*(3+9)

What you should actually be saying is:

Well, 2(3+9) is the same as (2*(3+9))
Biffo the Bear is offline   Reply With Quote
Old 09-04-2011, 15:08   #163
VioletSummers
Forum Member
 
Join Date: Jan 2011
Posts: 862
Quote:
Originally Posted by husted View Post
The point of brackets is to clarify the expression to make clear what should be done first. But if you have a number outside, then this needs to be operated on everything inside the brackets :
So if you have:
2(9+3)
then this is the same as
2x9 + 2x3.
But this isnt clear, so we write this as :
(2x9) + (2x3)

So a clearer way to put the expression might be

48 ÷ ((2x9) + (2x3))

which equals 2.
Come on people... read this post ^. Husted is right.
Quote:
Originally Posted by Bedlem View Post
Hey, it's just my opinion! I dropped out of Maths when I was 15 so understand that I'm 'uneducated' but applying my own logic.

(But ye the answer is still 2)
But it matches with what I'm 100% sure is right, so woo!
Quote:
Originally Posted by John259 View Post
That is wrong, because the 2 is outside the brackets in the original expression, not inside them.
Wrong. Numbers outside the brackets affect everything inside them.
VioletSummers is offline   Reply With Quote
Old 09-04-2011, 15:09   #164
Biffo the Bear
Forum Member
 
Join Date: Jul 2005
Location: Nottinghamceistershire
Services: Fusion powered warp drive
Posts: 21,627
I think we're seeing an overall victory for 2s here, which is right because logic dictates as thus!
Biffo the Bear is offline   Reply With Quote
Old 09-04-2011, 15:09   #165
John259
Forum Member
 
Join Date: Nov 2003
Location: Norwich, Norfolk, UK
Services: LG LCD IDTV; Tacolneston TX; Virgin Media ADSL
Posts: 11,037
Quote:
Originally Posted by Biffo the Bear View Post
Ah, but it's okay to add a multiplication sign which wasn't there before?

Like I said earlier, if you're going to say:

Well, 2(3+9) is the same as 2*(3+9)
That is correct.
Quote:
What you should actually be saying is:

Well, 2(3+9) is the same as (2*(3+9))
That is incorrect. Brackets only affect what is inside them.
John259 is offline   Reply With Quote
Old 09-04-2011, 15:09   #166
lorry
Forum Member
 
Join Date: Jul 2002
Posts: 2,270
I'm in the 2 camp!

work out the brackets and its associated number first which is

2 x 12 = 24

then work left to right

48 ÷ 24 = 2

Simples.
lorry is offline   Reply With Quote
Old 09-04-2011, 15:10   #167
Biffo the Bear
Forum Member
 
Join Date: Jul 2005
Location: Nottinghamceistershire
Services: Fusion powered warp drive
Posts: 21,627
Quote:
Originally Posted by John259 View Post
Brackets only affect what is inside them.
Or what is cojoined to them, without a multiplication sign separating them.

a(b+c) = (a*(b+c))
Biffo the Bear is offline   Reply With Quote
Old 09-04-2011, 15:12   #168
John259
Forum Member
 
Join Date: Nov 2003
Location: Norwich, Norfolk, UK
Services: LG LCD IDTV; Tacolneston TX; Virgin Media ADSL
Posts: 11,037
Quote:
Originally Posted by Biffo the Bear View Post
Or what is cojoined to them, without a multiplication sign separating them.

a(b+c) = (a*(b+c))
No. Your outer brackets are incorrect.

a(b+c) = ab + ac (the distribution rule) but no outer brackets are implied.
John259 is offline   Reply With Quote
Old 09-04-2011, 15:13   #169
VioletSummers
Forum Member
 
Join Date: Jan 2011
Posts: 862
Quote:
Originally Posted by John259 View Post
That is correct.

That is incorrect. Brackets only affect what is inside them.
The numbers outside the brackets affect what's inside them. Numbers in the brackets don't affect anything else, which is why they are in brackets.


BODMAS - Brackets are first.

The 2 is attached to the bracket as no-one has put a multiplication sign there. 2(9+3) = (2x9)+(2x3)=24

48/24=2
VioletSummers is offline   Reply With Quote
Old 09-04-2011, 15:15   #170
Biffo the Bear
Forum Member
 
Join Date: Jul 2005
Location: Nottinghamceistershire
Services: Fusion powered warp drive
Posts: 21,627
For the love of God. RIGHT, WHICH ONE OF THESE MAKES SENSE:

48 lamb chops / 2(9+3) butchers
48 lamb chops / 24 butchers
2 each

48 lamb chops / 2(9+3) butchers
48 lamb chops/2 butchers * 12
288 each
Biffo the Bear is offline   Reply With Quote
Old 09-04-2011, 15:18   #171
John259
Forum Member
 
Join Date: Nov 2003
Location: Norwich, Norfolk, UK
Services: LG LCD IDTV; Tacolneston TX; Virgin Media ADSL
Posts: 11,037
48÷2(9+3)

= 48 ÷ 2 x 12

= 24 x 12

= 288

In BODMAS, division and multiplication have equal priority and there are no brackets around 2 x 12 so you work left to right.
John259 is offline   Reply With Quote
Old 09-04-2011, 15:23   #172
VioletSummers
Forum Member
 
Join Date: Jan 2011
Posts: 862
Quote:
Originally Posted by John259 View Post
48÷2(9+3)

= 48 ÷ 2 x 12

= 24 x 12

= 288

In BODMAS, division and multiplication have equal priority and there are no brackets around 2 x 12 so you work left to right.
But why haven't you calculated the brackets first?

The 2 is NOT separated from the brackets with a multiplcation symbol and therefore must be calculated WITH the brackets.
VioletSummers is offline   Reply With Quote
Old 09-04-2011, 15:30   #173
AlphaK
Forum Member
 
Join Date: May 2008
Location: Slaving over a hot laptop
Posts: 3,610
Quote:
Originally Posted by John259 View Post
No. Your outer brackets are incorrect.

a(b+c) = ab + ac (the distribution rule) but no outer brackets are implied.
which would give

48 ÷ 2*9 + 2*3 = neither 288 or 2
AlphaK is offline   Reply With Quote
Old 09-04-2011, 15:31   #174
John259
Forum Member
 
Join Date: Nov 2003
Location: Norwich, Norfolk, UK
Services: LG LCD IDTV; Tacolneston TX; Virgin Media ADSL
Posts: 11,037
Quote:
Originally Posted by VioletSummers View Post
But why haven't you calculated the brackets first?
I have. What's inside the brackets is 9 + 3 which is 12.
Quote:
The 2 is NOT separated from the brackets with a multiplcation symbol and therefore must be calculated WITH the brackets.
No. I don't know where you're getting that from but it isn't right. There is no such rule.
John259 is offline   Reply With Quote
Old 09-04-2011, 15:34   #175
VodkaLove
Forum Member
 
Join Date: Feb 2011
Posts: 340
It is 2.
VodkaLove is offline   Reply With Quote
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search

 
Forum Jump


All times are GMT +1. The time now is 21:55.